This invention relates to a liquid-ring pump for transporting a medium of changing amounts of liquid and gas. More particularly, this invention relates to such a liquid-ring pump provided with a mechanism for replenishing working liquid in the liquid ring during pump operation.
A liquid-ring pump comprises a housing including a pair of end bells, at least one of the end bells being provided with an inlet and an outlet for a gas to be pumped. A vane wheel is disposed in the housing between the end bells, the vane wheel being rotatably and eccentrically supported by the end bells for forming a liquid ring in the housing during operation of the pump. Upon formation, the liquid ring is disposed circumferentially with respect to the vane wheel. At least one control disc is provided in the housing between the one of the end bells and the vane wheel, the disc being formed with a suction slot associated with the inlet of the end bell and a pressure slot associated with the outlet.
Such a liquid-ring pump is provided with an arrangement of injection nozzles in the inlet region between the control disc and the juxtaposed end bell. The injection nozzles feed a predetermined amount of working liquid to the inlet region of the pump independently of the liquid level in the end bell. The rate at which the new working liquid is conveyed to the end bell is determined in accordance with expected transport of the working liquid from the pump with the gas being pumped, the rate or amount of added working liquid being selected to maintain a constant amount of liquid in the rotating ring. If only gas is transported by the pump, the constant addition of working liquid results in an increase in the liquid in the rotating ring, which increase causes a higher load on the liquid-ring machine.
An object of the present invention is to provide an improved liquid-ring pump of the above-described type.
Another, more particular, object of the present invention is to provide such an improved pump wherein the amount of liquid in the rotating ring is maintained at a substantially constant level.
Another particular object of the present invention is to provide such a pump wherein the working liquid supplied to the pump through the injection nozzles at a given pressure is automatically throttled from a maximum amount required when a mixture of gas and working liquid is transported to a smaller amount when only gas is transported by the pump.
Another object of the present invention is to provide such a pump in which the load on the pump is essentially constant.
Yet another particular object of the present invention is to provide such a pump in which working liquid is saved with increasing amount of liquid transported with the gas by the pump.
A further object of the present invention is to provide such a pump in which the amount of working liquid added to the supply in an end bell can be throttled practically down to zero.